Harvester air separator

ABSTRACT

A harvester for beans and like crop includes a pick-up reel having a width equal to the overall width of the harvester and leading to a first, cleaning, conveyor which terminates at an air passage incorporating a fan for generating a generally vertical air flow. Where the vertical air passage meets the cleaning conveyor, a rotary valve is provided which permits the passage of the beans and other parts of the crop but prevents or at least restricts the passage of the air flow into the space above the upper run of the conveyor. The rotary valve may take the form of a rotary vaned assembly having six vanes each of which is secured to one face of a hexagonal shaft and various forms of rotary valve are also described.

SUMMARY OF THE INVENTION

This invention relates to harvesters and in particular bean harvesters.

Numerous bean harvesters have been proposed and some of these proposalshave been constructed and made available on the market. A successfulbean harvester has the following features:

1. the crop collected should be as clean as possible;

2. the loss of crop should be kept to a minimum;

3. the damage to standing crop not yet harvested should be kept to aminimum;

4. the harvester should be highly maneuverable and the parts should bereadily accessible;

5. the harvester must be robust and capable of withstanding the arduousconditions and absence of maintenance encountered in the field;

6. the overall weight should be kept as low as possible;

7. the harvester should be capable of accommodating without loss ofcrop-picking efficiency, variations in ground contour;

8. the harvester should be capable of harvesting crop irrespective ofwhether or not it is planted in rows;

9. it should be possible to clean the machine without substantialdismantling;

10. the hopper or other store should be capable of discharge to a lorryor other vehicle without appreciable delay and irrespective of theheight of the other vehicle; and

11. the harvester should be highly maneouvrable on the roads and whenmoving away from the fields.

Various harvesters have been proposed which partially satisfy theserequirements but as will be appreciated, taken together, these areonerous and not readily fulfilled.

It is an object of the present invention to fulfil as many as possibleof these objectives in a machine which is not unduly complex and thecost of which remains competitive.

According to the present invention there is provided a cleaning stage ofa harvester for beans or the like comprising an inclined conveyor formaterial to be cleaned, a casing speed from the conveyor, movable valvemeans at the upper run of the conveyor co-operating with an adjacentpart of the casing and with the conveyor, and means for producing an airflow in a passage to separate lighter from heavier crop components, saidmovable valve means serving to permit the delivery of the material onthe upper run of the conveyor to the passage but to restrict air flowbetween the casing and the upper run of the conveyor.

Further according to the present invention, there is provided aharvester assembly arranged for mounting on a tractor, said assemblycomprising a forward crop pick-up device, a first, rearwardly-extending,conveyor arranged to receive crop from the pick-up device with the endthereof adjacent to the pick-up device being spaced closely thereto andan end thereof remote from the pick-up device lying adjacent a closurearrangement capable of permitting the passage of crop on the conveyorupper run while restricting air flow to the conveyor upper surface,means defining a generally vertical passage immediately downstream ofsaid remote end of the conveyor, said passage communicating with asuction device to produce an upward air flow therein whereby at leastpartially to separate heavier from lighter elements of the crop receivedin the passage from the conveyor, and said passage being partiallyobstructed at its lower end by a second, transversely-extending,conveyor for conveying away said heavier elements and the remaininglighter elements a third, rearwardly-extending, conveyor fortransporting the heavier elements and the remaining lighter elements toa second, generally vertical passage, said second passage having asecond suction device communicating therewith to produce an upward airflow whereby further to separate remaining lighter elements from theheavier elements, and a fourth conveyor one end of which defines,together with a rearward end of the third conveyor a part of the secondpassage, said fourth conveyor serving to conduct the heavier elements toa store.

Yet further according to the present invention there is provided a beanharvester assembly comprising a crop pick-up device having a width equalat least to the overall width of the harvester assembly as a whole and adevice for separating heavier from lighter elements of the cropdelivered thereto from the pick-up device, said separating device havinga width substantially equal to that of the pick-up device.

Still further according to the present invention there is provided abean harvester assembly comprising a pick-up device for the crop, aconveyor for receiving crop from the pick-up device and a separatingdevice formed by a generally-vertical passage in communication with anair flow generator, the pick-up device, the conveyor and the separatingdevice being pivotal in relation to remaining parts of the harvesterassembly to facilitate movement of the assembly when it is in operation.

An embodiment of a bean harvester assembly in accordance with theinvention will now be described by way of example, with reference to theaccompanying diagrammatic drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows an outline side elevation of a bean harvester assembly inaccordance with the invention;

FIG. 1B is a front elevation of the harvester assembly of FIG. 1A;

FIG. 1C is a plan view of the harvester assembly of FIGS. 1A and 1B;

FIGS. 2A to 2H illustrate possible alternative constructions of onedetail of one cleaning stage of the harvester assembly as illustrated inFIG. 1;

FIG. 3A is a side elevation of a hopper arrangement of the harvesterassembly showing in broken lines the hopper being tilted in an elevatedcondition towards a discharge configuration;

FIG. 3B is a fragmentary side elevation showing one of the cleaningstages of the harvester assembly;

FIG. 4 is a side elevation of an alternative hopper arrangement; and

FIG. 5 is a diagram of a hydraulic system for controlling the level of apick-up device of the harvester assembly and for actuating pick-updevice lifting cylinders.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, in general terms the bean harvesterassembly comprises a forward pick-up device 10, which supplies the cropto a first, rearwardly-extending, conveyor 12, arranged immediatelyrearwardly of the pick-up device 10, a first crop-separating or cleaningstage or section 14 arranged rearwardly of the first conveyor andincluding a bank of blowers or fans 16 by which 90% of the crop productis separated from leaves and other waste materials. Beans,partially-cleaned at the first cleaning stage, fall onto a second,transverse, conveyor 9. Rearwardly of the crop-separating section 14, athird, rearwardly-extending conveyor 18 is provided which leads to asecond crop-separating or cleaning stage or section 20 which includes atleast one fan or blower 22 or other suction device and co-operates toremove the crop product with an inclined, rearwardly-extending, fourthconveyor 24 leading to the inlet of a hopper 26. The conveyor 24 has,mounted on stationary structure thereof, a further fan which forms partof a third, and final cleaning stage or section 28. The hopper 26 ispreferably mounted on an overhanging framework 29 in order at leastpartially to counterbalance the weight of the pick-up device 10 andassociated parts arranged to be mounted forwardly of the tractorillustrated very diagrammatically at 30.

Turning now to details of the harvester assembly, it is arranged asstated above to be mounted on a tractor which reduces the initial cost,provides for greater flexibility in use and has the advantage that thepower plant incorporates components which are usually readily locallyavailable to the user. The approximate position of the eyes of thedriver of the tractor is indicated at 32.

The pick-up device 10 comprises a reel 11 having a plurality ofgenerally radially-extending tines 13 only one of which is illustratedin the drawing for the sake of simplicity. The reel 11 is mounted forrotation by means (not shown) on a frame (not shown) extending generallylongitudinally on both sides of the tractor. The drive means maycomprise chains driven by a hydraulic motor (not shown). The tines 13 ofthe pick-up reel 11 have outer portions which are slightly inclined tothe generally radially-extending inner portions thereof. Thisarrangement assists in lifting the bean plants during the pickingaction. A casing end portion 17 of sheet metal is slidably mountedwithin an end portion 19 of a main picking reel casing 21 (see FIG. 1A)and follows closely the periphery of the outer tips of the picking reeltines 13. This casing portion 17 is made adjustable so that when largebean plant height differences are encountered, product loss in that areais avoided. The upper part of the casing 21 becomes progressivelyfurther spaced from the periphery of the tines 13 and extends in aninclined direction generally rearwardly to a transverse ridge 23 fromwhich it is inclined downwardly and rearwardly to an edge adjacent to arear end of the inclined first conveyor 12 of the harvester.

The first conveyor 12 extends at an angle of approximately 20° to thehorizontal from a position closely spaced to the reel 11 atapproximately the 9 o'clock position thereof and the conveyor is mountedfor movement over two rollers of conventional design. The belt of theconveyor 12 carries equally-spaced 10 mm. transverse flights (notshown). The first conveyor may be chain driven from the same hydraulicmotor as that used to drive the reel 10. Alternatively, two hydraulicmotors may be incorporated, one on each side of the harvester, bothbeing drivingly coupled to the reel and the first conveyor. The edgehereinbefore referred to adjacent the upper end of the first conveyor 12connects with an upwardly-inclined portion 21' of the casing which inturn connects with a further upwardly-inclined portion 21"; the casingpartially accommodates a rotary flap valve or other rotary vaned member25 incorporating four or possibly six flexible vanes (described indetail hereinafter). The vanes almost touch the inclined portion 21' ofthe casing referred to and the path of the tips of the vanes also comesinto close proximity with the upper end of the first conveyor 12 at aposition where it passes around the upper roller of the first conveyor.The rotary vane member 25 is so rotated that the tips of the flexiblevanes move in the same sense as, and with a peripheral speed equal tothe speed of the upper run of conveyor 12. The diameter of the member 25will be approximately twice that of the adjacent conveyor belt roller.This arrangement assists the cleaning efficiency by preventing stray airflows from upsetting the fan induced flows in the first cleaning stageor section. The ratio of the diameter of the rotary vane member 25 tothe diameter of the upper belt roller 97 may be in the range 1:1 to 2:1.

Alternatives to the flap valve illustrated in FIG. 1A are shown in FIGS.2A to 2H. These will be described hereinafter.

The rotary vane member 25 with flexible flaps or vanes serves tominimize the passage of air between the upper end of the conveyor 12 andthe casing portion 21' since otherwise substantial air flow will bedrawn by the fans from the area above the conveyor 12. This air flow,since it does not pass through the product to be cleaned, will notremove leaves and waste from the beans. Further, this air flow wouldobstruct efficient air flow through a passage 33 extending between thelower run of conveyor 12 and the conveyor 9, such that a very poorcleaning efficiency in this first stage would be obtained.

The second, transverse, conveyor 9 lies immediately rearwardly of andbelow the upper end of the first conveyor 12 and defines the bottom ofthe first air separating or cleaning passage 33 which extends over thewhole width of the harvester and corresponds at least in substance tothe width of the pick-up reel 11. The air flow 29 (indicated by a brokenline arrow) through the passage 33 passes to the bank 16 of five fans 31driven by hydraulic motors through a V-belt transmission (not shown). Aswill be apparent from FIG. 1A the lower end of the passage 33 is verywide thus avoiding high air velocities which might draw loose soil intothe passage under dry and dusty conditions which are sometimesencountered at harvest time.

The transverse conveyor 9 extends across a major proportion of the widthof the first cleaning passage and its direction of motion is such thatthe upper run thereof discharges a mixture of crop product and wasteonto a lower end portion of the third conveyor 18 which is mounted toextend along one side of the tractor, i.e., laterally of thelongitudinal centre line of the harvester assembly.

Downstream of the bank of fans 16 there is a discharge passage 35 whichends in a diffusing section 37 serving to reduce the velocity of air andof the discharged leaves and other waste for the purpose of minimizingblowing of dust under dry conditions. The bank of fans 16 together withthe discharge passage 35 is mounted at a pivot connection 34 (see FIG.1A) or fan hinge point on the framework of the pick-up, which matcheswith the end of cover 21 and two hydraulic cylinders 39 keep thecleaning arrangement as a whole in its elevated condition (see FIG. 3B).

As such, this cleaning arrangement can be pushed down to provide maximumvisibility for the machine driver (see FIG. 1A) by cylinders 39 when thepick-up device as a whole has been lifted for road transport. Thishydraulic control is combined with a hydraulic levelling system of thepick-up device as will be described hereinafter with reference to FIG.5.

The visibility provided is at least as good as when the pick-up deviceis in its working position in the field.

The third conveyor 18 extends rearwardly at a slight angle to thehorizontal of, for example, 15° to 20° and like the first conveyor isprovided with transverse bars or flights (not shown).

The rearward end of this third conveyor 18 is arranged to discharge thecrop product and remaining dirt and leaves onto a lower end portion ofthe fourth conveyor or elevator 24. The adjacent ends of these conveyors18 and 24 are spaced apart to enable passage of a generally vertical airflow indicated by broken line arrows 40 which flow is drawn upwardly bythe fan or blower 22 rotatable about a horizontal axis transverse to thelongitudinal direction of the harvester. As will be apparent from arrows40 illustrated in FIG. 1A, the trajectory of the beans or other usefulproduct crop is approximately at right-angles to the direction of theairflow, thus ensuring as far as possible that the leaves and otherwaste are almost completely separated from the beans. The fan 22 of thesecond cleaning stage or section is arranged to discharge the air andwaste on the same side of the tractor as the elevator 24 in the alreadyharvested area but because of the low velocity of the discharge airthere will be little disturbance of the soil, even under dry conditions.

The fourth, rearwardly-extending conveyor or elevator 24 has appropriateflights of from 75 to 100 mm. height (not shown) which ensure that thebean pods are satisfactorily elevated to the upper end of the conveyorwhere they are discharged onto the transverse hopper conveyor 56 whereindicated by chain line arrows. The hopper conveyor 56 discharges intothe hopper 26.

At the discharge end of the elevator 24 there is a fan 47 rotatableabout an inclined axis, see FIG. 1A, positioned on the elevator frame.Split ducting 48 controls the air flow through the product and thetrajectory of the product on to a hopper conveyor 56, which ejects thebeans into the hopper. The fan 47 and a first part of the ducting 48 donot move when the hopper is tilted for dumping. The second half of theducting and the hopper conveyor 56 are mounted on the hopper andthereafore they will move with the hopper during dumping. As in thepenultimate cleaning stage, the fan 47 draws an air mass through theproduct which traverses this air flow first at right-angles and then inthe opposite sense as indicated by the full line arrows 44. Anyremaining trash, dust or sand is removed at this stage of operation asindicated by broken line arrows 46 and discharged on to the harvestedarea. This final cleaning stage may be omitted if cleaning is adequatelyachieved by the earlier stages.

The second half of the ducting 48 is made of portions inclinedlengthwise as can be seen in FIG. 1A and transversely as can be seen inFIG. 1C. These ducting portions provide a spread-out of the beans ontothe wide hopper conveyor 56 so that the hopper will be evenly filledlengthwise as indicated in FIG. 1A and 1C by chain lines.

An oil reservoir (not shown) for the hydraulic system is mounted on aframe laterally of the hopper 26, and thus balances the off-centreloading of the pick-up device and the conveyors 18 and 24 which extendalongside the tractor.

Two alternative hopper systems may be used. The first being a simple"tilt-side" hopper as seen in FIGS. 1B and 3A. The hopper 26 is tiltedsuch that the right-hand wall assumes an inclination of approximately45° to allow a complete removal of all product into a mobile receptacle,such as a lorry or truck (not shown).

To avoid dangerous and difficult manoeuvering for this receptacle to getclose enough to the machine to receive the product without losses, thehopper will first be swung out as can be seen in FIG. 3A. The hopper 26is for this reason attached pivotally at 27 to a pivot-frame 49 which,in turn, is pivotally mounted at 49A on the hopper supporting frame.

When hydraulic actuators 52 exert a force against the hopper 26 thiswill swing out about 27 until pins 49B of bars 49C have travelled alongthe slots 49D in the pivot frame and limit further lateral movement ofthe complete structure. The actuators 52, by continuing to exert a forceon the hopper, cause it to pivot fully around pivot 27 into the dumpposition 26B (chain lines).

When the actuators 52 are retracted, the hopper 26 will first come downagain and then be retracted about pivot 27 into its initial position.

A second, alternative, hopper system is shown in FIG. 4. Most of thehopper 126 is formed from conventional sheet metal, except for one sidewall 128 which is formed by an upper run of a conveyor 130 reinforced tocarry the total product weight carried by the hopper. An initial part ofthe stroke of the hydraulic actuators 152 lifts the hopper and pivots itabout pivot 127 spaced by distance D below an upper roller of the hopperwall conveyor 130. The hopper is lifted as the actuators continue theirstrokes until the hopper wall conveyor 130 has an inclination ofapproximately 5° to the horizontal (chain lines in FIG. 4).

Dumping is assisted by driving the hopper wall conveyor 130 by ahydraulic motor (not shown) so that the total product mass isprogressively and controllably discharged from the hopper and dumpedinto a mobile receptacle alongside the harvester. The distance "D"provides a safe overhang, a similar limit being applied to the hopper ofFIG. 3A. Advantages of the system of FIG. 4 are:

dumping can be controlled, e.g. when the drive of the conveyor isstopped, the product stops in that position;

the hopper need not be lifted too far so that the centre of gravity ofthe total machine remains low and as such stable;

the hopper need not swing out significantly so that the centre ofgravity remains close to the machine axis, and again stability results.

The picking reel 10, the conveyors 12, 9 and 18 are all mounted on aframework pivotal at 62 on a fixed frame (either frame shown). One ortwo hydraulic actuators (not shown) act directly between the fixed andpivotal frames to raise the pivotal frame when the harvester isinoperative. The bank of fans 16 and associated ducting is separatelypivoted to retract it downwardly and thus avoid obstructing the drivingview. The absence of springs in the connection between the framesensures that the pivotal frame will not bounce when operating in thefield.

Referring now to the possible alternatives to the arrangement whichlimits the flow of air over the exit of the first conveyor, asillustrated in FIG. 2A the rotary vane valve 25 is replaced by valvemeans in the form of a similar transversely-extending member 70incorporating four elongate brushes. In general, such an arrangementwould be less satisfactory than the preferred arrangement since althoughflexible, brushes unless very dense, and hence costly, have a tendencyto pass a substantial airflow in themselves.

In the arrangement illustrated in FIG. 2B, the vanes are replaced byrubber flaps 72 each mounted on a transverse bar 74 secured to a shaft76 of the valve. The operation of this arrangement would in substance bethe same as the preferred arrangement described in detail above.

In the modification illustrated in FIG. 2C, the rotary vane valve 25 isreplaced by a spring-loaded single flap 80 but the spring loading mustbe light in order to avoid damage to any crop product and it isdifficult to achieve a successful compromise in which the spring loadingis sufficient light to prevent this damage but sufficiently strong toprevent the flap being moved by the suction effect caused by the bank offans 16.

Alternatively the flap 80 may be locked mechanically in selectedpositions. This, however, can be dangerous for block-ups of productagainst this fixed flap as the passage must be kept small to reduce thesucking of useless air.

FIG. 2D includes an auxiliary belt 82, a lower run 84 of which isinclined and is spaced from the upper end portion 86 of the firstconveyor belt 12. This auxiliary belt has the advantage that crop damageand block-up is minimized but unless the belt is spring mounted in someway, there is a risk of crop damage and block-up in the event of a largenumber of beans attempting to leave the discharge end of the conveyor 12simultaneously.

FIG. 2E shows a modification of the arrangement of FIG. 2D in that thebelt is provided with transverse slats 88. These have a similar effectto the rubber flaps of the embodiment of FIG. 2B and the mode ofoperation is also similar.

In the modification illustrated in FIG. 2F airflow is limited by arubber flap 90 depending from a sheet member 92 itself secured to anunder-surface of the interior of the casing 21. Although believed to besatisfactory in operation, there is a risk that progress of the beansand leaves of the bean plants will be retarded if the flap exerts toomuch influence thereon or alternatively that if the flap is sufficientlyflexible it will be deflected by the suction applied. It will be notedthat this flap 90 is spaced from the end of the first conveyor and thishas the advantage that any air leakage at the rubber flap will have areduced velocity by the time it reaches the narrowest point between thecasing and the roller of the first conveyor.

In the modification illustrated in FIG. 2G the belt of the firstconveyor 12 is itself provided with slats 94 which are rigid and willtend to prevent any airflow passing between the conveyor and the upperstationary casing because of the protective effect that the slats exert.

In the final modification illustrated in FIG. 2H, the valve meanscomprises a hexagonal section shaft 95 to each flat of which a flexiblerubber flap 96 is secured. The upper roller 97 of the conveyor 12 shouldhave a larger diameter than that of the lower roller and the centre ofthe shaft 95 is displaced rearwardly of the centre line of the upperroller 97 of the belt 12. With this valve means the belt 12 preferablyhas no slats or flights, but the operative surface must then be rough.This alternative reduces turbulence adjacent the valve and excessiveturbulence in the vertical passage carrying airflow 29 can be reduced bycurved air guide 29' extending along one side of one edge of thetransverse conveyor 9.

As hereinbefore referred to, it is important that in operation thepicking reel shall maintain the required level at all times sinceotherwise the pick-up reel will either tend to pick up dirt and stonesas well as crop, if too low, or will miss valuable crop if too high. Alevelling system as disclosed in our co-pending application Ser. No.693,615, filed June 7, 1976, entitled Improvements In Or Relating toHarvesters can be incorporated in the bean harvester in accordance withthe invention and one skid or ski of such a system is indicated at 60 inFIG. 1A. Alternatively, sensing rollers or wheels can be used.

A dirt scraper will be mounted to remove dirt from each roller or wheel.As in the ski construction the wheels will be made adjustable forheight.

As mentioned above, the position control of the full width firstcleaning stage is combined with the pick-up levelling system (See FIG.5).

When a valve 100 of the levelling circuit is in position "2", acontinuous oil flow from line 102 provides accurate levelling of thepick-up device by means of cylinders 103 (only one shown), leaving asmall amount of the pick-up device weight on the ground-sensing skids 60(FIG. 1A) or wheels, as controlled by an adjustable relief valve 104.Actuators 39 for the cleaning fan arrangement are then retracted andshut off from the system.

By means of the valve 100, the pick-up device can be lifted when settingthe valve in position "0" as then the adjustable relief valve 104 isshut off and only a higher set relief valve 108 provides enough pressureto lift the complete pick-up device. In this position also the fanactuators 39 remain retracted.

When the machine is driven for a long period of time on the road, thepick-up device is mechanically locked and the valve 100 switched intoposition "1" so that the oil returns unrestricted to the oil tank. Forbetter visibility for the driver a spring-actuated valve 110 is switchedinto the "1" position connecting the fan actuators 39 with the oil tank(not shown) via a flow-restricting valve 112 serving to control thespeed of the downwards movement of the cleaning fan arrangement underits own height. Whenever the pick-up is lowered again for operation,position "2" of valve 100, the oil is immediately directed to thefan-actuators 39 so that the cleaning arrangement will always be in theworking position. The valve 110 is therefore provided as aspring-actuated valve which reinstates the initial "0" position(disconnecting the oil tank when the lever thereof is released.

The mode of operation of the bean harvester as hereinbefore described isas follows:

The rotary pick-up reel 11 rotates, as viewed in FIG. 1A, in theanti-clockwise sense and bean plants are up-rooted by the tines 13thereof and are projected within the casing 21 onto the upwardly andrearwardly moving upper run of the first conveyor 12. Below the casing21, the lower roller of the belt 12 lies closely adjacent the peripheryof the tines 13 of the reel and at less than one half of the height ofthe reel thereby preventing losses. The speed of rotation of the reel issuch that plant material follows trajectories on to the upper run of theconveyor 12. The belt 12 has a width at least equal to the width of thereel, which is itself at least as wide as the carrying tractor, so thatthe plant material is not concentrated at the first cleaning stage orsection 14.

At the first cleaning stage the fan bank 16 serves to draw upwardly anair flow as indicated by broken line arrows 29, the air being drawn inbetween the upper one 97 of the two rollers of the conveyor 12 and thesupport structure of the transverse conveyor 9. The rotary valve 25 (oris modifications) having flexible flaps (or equivalents) permits thepassage of plant material into the first cleaning stage without drawingsubstantial quantities of air from within the casing 21. If excessiveair were to be drawn from the casing 21 the separation would beadversely affected. By provision of the bank of fans 16 and thecorrespondingly wide casing, the thin distribution of the plant materialprovided by the belt 12 is maintained at the cleaning section itself andleaves, stems and dirt are drawn upwardly by the bank of fans whilst therelatively heavier and less aerodynamically susceptible beans themselvesfall onto the transverse conveyor 9. The shape of the passage limitingairflow 29 is such that vortices are produced approximately at the levelof the rotary valve 25 or a little above that level so that the leavesand lighter material are taken up in the air flow whilst the heavierbeans fall onto the conveyor. however, excessive turbulence is preventedby the air guide 29'. Some vortices are desirable because, under certainconditions it is possible that a bean, particularly if resting on a leafand lying transversely to the air flow, will be carried upwardly. If,however, it passes through a vortex the effective surface area will besubstantially reduced as the bean moves into alignment with the generaldirection of the air flow and will fall, as is required to avoid losses.Because of the large cross-sectional area of this passage (extendingacross the full width of the harvester) the air velocities are kept lowand the discharge through the ducting 35 and diffuser 37 is such thateven under dry conditions dust problems are not created. The removedmaterial is returned directly onto the field from which the beans havejust been removed.

The beans and remaining dirt, leaves and stems received on the conveyor9 are discharged onto the longitudinally-extending third conveyor 18.

The second cleaning stage or section 22 is provided at the downstreamend of the conveyor 18 and the upstream end of the elevator conveyor 24.The fan 22 provides within associated ducting an upwardly-directed airflow so that dirt, leaves and other items are drawn upwardly while thebeans are received on the flights of the conveyor 24. At this secondcleaning stage the mass flow of air is substantially less than at thefirst cleaning stage, but as will be appreciated the amount of materialto be removed is also substantially smaller. As for the first cleaningstage, the material is discharged directly onto the ground which hasjust been harvested.

As will be apparent from the position of the eyes 32 of the tractordriver, he will have a good view of the material as it is conveyed alongthe conveyor 18 and since, under proper operational conditions a verysubstantial part of the trash is removed, he can readily assess by eyeif any malfunction is occurring at the first cleaning stage.

The elevator conveyor 24 discharges on to the transverse conveyor 56which in turn discharges into the hopper 26 and the discharge zonebetween the conveyors 24 and 56 may also constitute a third cleaningstage. If the third stage is incorporated the fan 47 provides anupwardly-directed air flow which serves to remove any remaining dirt andleaves, stalks and so on and these are discharged downwardly laterallyof the hopper on to the ground which has just been harvested.

When the hopper 26 has received a full complement of beans it is raisedand tilted by means of the hydraulic actuators 52 to discharge the beansinto a lorry or trailer drawn up alongside the harvester. This dischargeis considerably aided by the embodiment of hopper with one moving wall.

As will be appreciated from the description given hereinbefore themounting of the harvester onto a conventional tractor gives rise to nogreat difficulties with regard to balance of the tractor since theweight of the pick-up assembly 10 at the front of the tractor 30 issubstantially counter-balanced by the overhanging hopper 26 and otherparts of the assembly at the rear of the tractor.

As already discussed, the levelling system ensures that irrespective ofundulations the reel 11 will be kept at substantially the same heightfrom the ground under all operational conditions.

Because of the provision of the hydraulic actuators 52 which raise thehopper before discharge, the vehicle receiving the beans can be anyconvenient height and a special low-loader trailer is not necessary.

Other advantages of the harvester assembly as hereinbefore particularlydescribed are that the overall height of the harvester assembly whenmounted on the tractor is kept to a reasonable level, the conveyors,even the elevating conveyor 24 leading to the hopper are not steeplyinclined, the use of a conventional tractor provides for considerableflexibility from the viewpoint of general forming. If a four-wheel drivetractor is used the well-distributed weight of the harvester assemblywill improve traction. Furthermore, a conventional tractor usually has avery good turning circle and the harvester assembly does nothing tointerfere with this turning circle and consequent manoeuverability. Thedrive for the harvester assembly presents no difficulties since it isreadily possible to make use of the conventional power take-off shaft ofthe tractor to drive hydraulic pumps and hence hydraulic motors coupledto simple chain and/or shaft drives (not shown in the drawings) to theindividual components.

Other advantages of the harvester assembly are that the driver has goodvisibility not only of the field ahead but of the individual componentsof the harvester assembly which lie ahead of him, the possibility offour-wheel drive plus a relatively light construction ensures that theharvester assembly can be used even under adverse weather conditions,the arrangement of a triple cleaning of the harvested material ensuresthat even bean varieties which are difficult to harvest and clean can beaccommodated and finally the harvester assembly has a high efficiencyboth with regard to capacity and the condition of the harvested beanswhen they are delivered from the hopper.

Although not directly connected with the harvesting operation, theprovision of hydraulic actuators to lower the full width cleaningarrangement ensures that the visibility when the tractor is being drivenalong a road is not impaired.

The levelling system fully described in our copending application Ser.No. 693,615 ensures efficiency in the picking up of the bean crop andits simplicity ensures satisfactory operation under agriculturalconditions. The arrangement of pick-up reel and the conveyors enablecontinued efficient operation irrespective of the adjustment of the reelto accommodate sloping and/or uneven ground.

In an unillustrated modification the second cleaning stage can beomitted so that the illustrated first and third stages become the onlystages incorporated.

Although the best mode contemplated for carrying out the presentinvention has been herein shown and described, it will be apparent thatmodification and variation can be made without departing from what isregarded to be the subject matter of the invention.

We claim:
 1. A cleaning stage of a harvester for beans and the likecomprising a casing; a bean picking reel and a conveyor for receivingand conveying the beans, leaves and vine fragments picked by said reel;said casing being formed with an arcuate portion shrouding the upperpart of the reel, a generally planar portion overlying said conveyor anda partition terminating at the discharge and spaced above the upperreach of said conveyor to define a gap; a moveable valve bridging thegap between said partition and the upper reach of said conveyor, saidvalve being substantially coextensive with the width of said conveyor;means for producing a stream of high velocity air from an area generallybeneath the lower reach of said conveyor extending into a passage-waylaterally adjacent and downstream of the discharge end of said conveyorand said valve to entrain and thus separate lighter from heavier cropcomponents; said moveable valve means serving to permit the delivery ofthe material from the upper run of the conveyor to the passage but torestrict and minimize air flow from the casing and the upper run of theconveyor whereby no substantial separation occurs thereat; and aconveyor adjacent said first mentioned conveyor to receive the remainingheavier crop components.
 2. A cleaning stage according to claim 1wherein the valve means is a rotary valve having flexible, generallyradially-extending vanes.
 3. A cleaning stage according to claim 2,wherein the valve means has six vanes and a shaft member having acorresponding number of faces, each vane being secured at aradially-inner edge portion to one of said faces.
 4. A cleaning stageaccording to claim 1 wherein the valve means is a flexible flap, pivotedon the casing and extending substantially to the upper run of theconveyor.
 5. A cleaning stage according to claim 1, wherein the conveyorhas transverse upstanding vanes which form the valve means inco-operation with an adjacent part of the casing.
 6. A cleaning stageaccording to claim 1 wherein the valve means comprises an endless beltcarrying upstanding flaps which co-operate with the conveyor and thecasing to limit the air flow over the conveyor.
 7. A cleaning stageaccording to claim 1 wherein the valve means comprises a rotary brush ofcylindrical outline.
 8. A cleaning stage according to claim 1, whereinthe valve means comprises an endless belt which co-operates with flightson the conveyor.
 9. A cleaning stage according to claim 1 wherein themeans for producing an air stream comprises a transversely extendingbank of fans pivotal as a bank about an axis transverse to the length ofthe harvester, and means pivoting said fans downwardly about said axiswhen the harvester is conditioned for road travel.
 10. A cleaning stageaccording to claim 9 comprising a fan casing with a downwardly-extendingoutlet passage for directing separated lighter crop elements to theground.